Does propolis affect the quality of life and complications in subjects with irritable bowel syndrome (diagnosed with Rome IV criteria)? A study protocol of the randomized, double-blinded, placebo-controlled clinical trial

BACKGROUND: Irritable bowel syndrome (IBS) is one of the most frequent and recurrent gastrointestinal diseases. However, up to now, no pharmacological agent has been approved to treat IBS. Emerging evidence showed that inflammation has a vital role in enhancing nervous system sensitivity and perception of abdominal pain in subjects with IBS. Propolis is an herbal substance with a broad spectrum of antioxidants, anti-inflammatory, and prebiotic properties, which might exert beneficial effects to reduce the severity of IBS. The current clinical trial aims to evaluate the efficacy of propolis supplementation on IBS. METHODS: This single-center, randomized, double-blind, placebo-controlled clinical trial will be performed to evaluate the effect of propolis supplementation in adult patients with IBS diagnosed with Rome IV criteria. Fifty-two eligible patients will randomly be allocated to receive a propolis tablet (450 mg, containing 100 mg polyphenol compounds) or identical placebo, twice daily for 6 weeks. The primary outcome of the trial is an improvement in IBS severity from baseline to the sixth week of intervention. The secondary outcomes include the change in weight, waist circumference, and IBS quality of life. We will use the paired sample t test or Mann-Whitney U test for the within-group comparison and independent sample t test or Wilcoxon rank-sum and chi-square test or Fisher’s exact test for the between-group comparison. Besides, a multivariable-adjusted mean effect will be computed using the ANCOVA test. DISCUSSION: We hypothesize that propolis supplementation would be useful for treating IBS through its antioxidants, anti-inflammatory, and prebiotic properties. This trial will show the results of propolis supplementation, whether positive or negative, on IBS. If the current trial confirms our hypothesis, propolis supplementation can be a new choice in adjunctive therapy of IBS. TRIAL REGISTRATION: Iranian Registry of Clinical Trials IRCT20190708044154N1. Registered on 26 December 2019. Updated on 13 February 2020. https://en.irct.ir/trial/40983 SPONSOR: Tabriz University of Medical Sciences, Tabriz, Iran